Soil and plant biodegradation of chlorpyrifos in fields of cauliflower and brussels sprouts crops

For the protection of early and summer cauliflower and brussels sprouts crops against root fly, the insecticide chlorpyrifos was applied at planting onto soil around the stem of the plant, or in the planting line. In the soil, chlorpyrifos (1) was transformed into the insecticide metabolites oxon, 0,0‐diethyl‐0‐(3,5,6‐tri‐chloro‐2‐pyridinyl) phosphate (2), and 3,5,6‐trichloro‐2‐pyridinol (3). The soil half life time of chlorpyrifos could be 2.8 times greater (42 days relative to 15 days) when the field history as to cauliflower monoculture and insecticide treatments was short (1 year), than when it was long (8 years). Rains and season also had cumulative effects on the chlorpyrifos soil half life times. In the leaves of cabbage, chlorpyrifos and compound 3 were observed at concentrations which were higher, especially when their soil concentrations were high. Chlorpyrifos and compounds 2 and 3 however were not detected in the “flower” of cauliflower, nor in the brussels sprouts itself, the limit of sensitivity being 0.02 ppm of fresh weight.     

Spatial variability in characteristics and trace metal levels in sediments from watercourses

Assessing sediment quality requires sampling designs which address variability. Often however, only one sample or composited sample is collected at a sample site. Existing studies on sediment variability or sampling strategies primarily concern lake or marine sediments. Two rivers and one canal were sampled to assess sediment variability. Further, it was determined if sediment contamination in running water could be predicted by using visual criteria and/or knowledge of the presence of depositional and erosion areas. Metal concentrations and sediment characteristics were measured in different visually distinct areas of the river. At all sample sites the coefficient of variance was relatively high for most sediment characteristics (1.4‐ > 100%) and metal levels (15.3–63.6%). In one river the majority of sediment characteristics variation was between two sediment types and detected by visually distinct differences. Significant differences in cadmium and zinc concentrations were also detected. Contrary to what was expected, cadmium, and zinc levels were highest in the coarse fraction. No differences were found in the second river. In the canal a greater concentration of fine grained sediments and metals were found in the deep areas. It was not possible to predict sediment areas with the highest levels of metal contamination using visual criteria or knowledge of the erosion and sedimentation pattern of the river.     

Psychological stress and marginalization as indicators of human carrying capacity in deforesting areas

SUMMARY

A scheme in which psychological factors are considered in effective forest management planning is proposed. A central role is played by human carrying capacity, the resilience of people to deal with the consequences of environmental degradation. Stress and marginalization are taken as indicators of human carrying capacity. A study in Côte d'Ivoire is described in which psychological stress and marginalization were studied in individuals from environments which show different degrees of degradation. Three related hypotheses are proposed: first that individuals living in or near a degrading forest are more stressed and marginalized than individuals in a reference group living in Abidjan; second that people living near the forest with the most sustained and severe degradation would be more stressed and marginalized; finally, that members of autochthonous cultural groups show higher stress and marginalization levels than members of migrant groups. The results of our study showed that people living near the degraded forest were more stressed but not marginalized unless the degradation was severe and sustained. Females were more stressed than males and members of both sexes from autochthonous cultural groups were more prone to stress and marginalization than members of migrant groups.     

Antipredator responses of koomal (Trichosurus vulpecula hypoleucus) against introduced and native predators

Antipredator behavior studies generally assess prey responses to single predator species although most real systems contain multiple species. In multi-predator environments prey ideally use antipredator responses that are effective against all predator species, although responses may only be effective against one predator and counterproductive for another. Multi-predator systems may also include introduced predators that the prey did not co-evolve with, so the prey may either fail to recognize their threat (level 1 naiveté), use ineffective responses (level 2 naiveté) or succumb to their superior hunting ability (level 3 naiveté). We analyzed microhabitat selection of an Australian marsupial (koomal, Trichosurus vulpecula hypoleucus) when faced with spatiotemporal differences in the activity/density levels of one native (chuditch, Dasyurus geoffroii) and two introduced predators (red fox, Vulpes vulpes; feral cat, Felis catus). From this, we inferred whether koomal recognized introduced predators as a threat, and whether they minimized predation risk by either staying close to trees and/or using open or dense microhabitats. Koomal remained close to escape trees regardless of the predator species present, or activity/density levels, suggesting koomal employ this behavior as a first line of defense. Koomal shifted to dense cover only under high risk scenarios (i.e., with multiple predator species present at high densities). When predation risk was low, koomal used open microhabitats, which likely provided benefits not associated with predator avoidance. Koomal did not exhibit level 1 naiveté, although further studies are required to determine if they exhibit higher levels of naiveté (2–3) against foxes and cats.     

Intrasexual competition,territoriality and acoustic communication in male strawberry poison frogs (<Emphasis Type="Italic">Oophaga pumilio</Emphasis>)

In many species male reproductive success is limited by access to females. Territoriality is one behavioural strategy which helps to acquire females. In the present study, we investigated the correlation between territory size and (1) female availability and (2) rate of intrusion by conspecific males in strawberry poison frogs, Oophaga pumilio. Males defended smaller territories in areas with a high female density and high rate of intrusion by conspecific males. Only males with high body condition values were able to establish territories in areas of high female density probably due to better fighting abilities. Moreover, dominant calling frequency was lower during agonistic interactions. Because only males with high body condition values were able to produce very low dominant frequencies, the acoustic properties appear to be an honest signal containing information about fighting abilities. Thus, the negative correlation between dominant frequency and mating success of males found in previous studies seems to be in part the result of intrasexual competition between males.     

The effects of anaerobic reactor post-treatments by rapid filtration systems and conventional techniques

Environmental Science and Pollution Research - Although anaerobic reactors are an excellent alternative in the treatment of domestic effluents, they have the disadvantage of requiring...     

Morphological responses and tolerance of a tree native to the Brazilian Cerrado Astronium fraxinifolium Schott to boron toxicity

Environmental Science and Pollution Research - The indiscriminate use of fertilizers and chemical pesticides can lead to boron contamination of the soil. Decontamination in general is expensive and...     

Correction to: Briquettes of acai seeds: characterization of the biomass and influence of the parameters of production temperature and pressure in the physical-mechanical and energy quality

Environmental Science and Pollution Research - A Correction to this paper has been published: 10.1007/s11356-021-16529-z     

The time of concentration application in studies around the world: a review

Environmental Science and Pollution Research - The time of concentration (Tc) is the main hydrological parameter used to characterize the response of a given Hydrological Response Unit (HRU) to a...